Compressor regulator and unloader



March 20, 1928. c. w. METZGAR COMPRESSOR REGULATOR AND UNLOADER Filed Nov. 5 1925 4 Sheets-Sheet 1 INVENTOR ms ATTORN Y March 20, 1928. 1,663,530

c. w. ME TZGAR COMPRESSOR REGULATOR AND UNLOADER Filed Nov. 5 1925 4 Sheets-Sheet 2 INVENTOR ihea'fvWMs? 0 HIS ATTOR Y March 20, 1928. 1,663,530

C. W. METZGAR COMPRESSOR REGULATOR AND UNLOADER Filed NOV. 5 1925 4 Sheets-Sheet 3 INVENTOR.

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ms ATTORNEY C. W. METZGAR COMPRESSOR REGULATOR AND UNLOADER Fil d N v, 5 1925 4 Sheets-Sheet 4 H l5 ATTORN Y Patented Mar. 20, 1928.

UNITED STATES PATENT, OFFICE.

CHESTER W. METZGAR, OF EASTON, PENNSYLVANIA, ASSIGNOR 'I'O INGERSOLL -RAND COMPANY, OF JERSEY CITY, NEW JERSEY, A CORPOlR'iA'lIOZhT OF NEW JERSEY.

COMPRESSOR REGULATOR AND ,UNLOADER.

Application filed Novembcr 3, 1925. Serial No. 66,492.

This invention relates to compressors, but more particularly to. a regulator and unloader.

One object of the invention is to secure an efiicient regulator and unloader for an installation in which there is another unit or prune mover in addition to the compressor, as for instance a mine hoist, which op;

erates intermittently. In such installations, in which both the compressor and hoist are electrically driven, the cost of vcurrent is frequently computed according to thepeak load for the day, regardless of whether cur rent is used continuously or not and if the compressor is running and the hoist is started up, the peak load isexcessively high. An object ofthis invention is therefore to keep the maximum demand charge; as low as possible by means of the regulating and unloading apparatus. I 7

Another object is to enable the compressor to be started and stopped from the main switch board of the plant, by distant con trol, which includes control of an auxiliary automatic device which may be an electroresponsive unloader for permitting the com-' pressor to run unloaded while the hoist is running, thus avoiding excessive peak loads.

A further object is to secure complete unloading by means of a by-pass connection on each cylinder of a multi-c'ylindercompressor as a duplex or a multistage compressor,

which provides a sixth step of unloading'on driven power unit, in the form of a mine hoist, both controlled from a common main switch board, p 7

Figure 2 is an enlarged detail side elevation partly in longitudinal section through the electro'responsive auxiliary device of the regulator and unloader for the compressor,

Figure 3 is a diagrammatic view of a dir.

plex compressor partly in sectional plan view having the regulator assembled there with,

Figure 4 is an enlarged detail sectional elevation of the pressure responsive regu lator and unlo-ader taken on the line l--l ofFigure 5 looking in the direction of the arrows. In this view theparts have been shown in oneplane for.betterillustration and to show the various ports, passages and valves, and

Figure 5 is a horizontal sectional view of the regulator on the line 5 -5 of Figure 4: looking in the direction of the arrows. Referring to the drawings, the installation shown diagrammatically in Figure 1 comprises the compressor having the cylindersA andB in this instance a duplex compressor being shown adapted to be con nected inthe usual nianner to the discharge tanlr or receiver C, the intake and discharge connections of the compressor being omitted for simplicity ofillustration; The discharge outlets of the cylinders are indicated at D- and E, andthe cylinders are provided with the usual pistons F and the inlet and dis charge valves G and H. The compressor is electrically driven by means oi the motorJ suppliedwith current from the mains K and leadsL carried-by the main switch boardO. on which the compressor switch P is mounted,

In the present instance, a second power unitis adapted to: operate in conjunction with the compressor and is, shownas a mine.

hoist Q having the drum R driven by the electric. motor S and having a starting box T fromjwhich 'the leadsU connect to the hoist switch V on the main switch board 0. A voltmeter W is preferably included in the circuits for indicating purposes.

The compressor is provided with a pressure responsive regulator and unloader X actuated in this instance by receiver pressure trom'the pipe a connecting the receiver C to thepoint b on the regulator casing and communicating with the diaphragm chamberc having the diaphragm (Z operatively connectedflto actuate the weighted lever e in accordance with variations in the receiver pressure. l

The regulator X is constructed similarly to and operates like the compressor regulator disclosed in Patent No. 1,430,578 granted to me October 3, 1922, with the exception, that in accordance with the present invention, I have added a sixth step to the reguand 4: with the correspondingly numbered pipes 1, 2, 3 and e on the regulator X. The auxiliary casing Y for the sixth step of unloading is connected by a pipe 5 to the unloader casings 0 of the by-pass va ves f.

All the unloader valves and by-pass valves are adapted to be held closed by a receiver pressure in the usual manner and they are assisted in opening by springs (not shown) when pressure is released from the valves successively. In operation as usual the pairs of valves 1, 2, 8 and i are 0 erated successively for loading and unloacing, but in the present instance, the tour by-pass valves 7 are all operated together as the last or sixth step of unloading for a purpose to be described which differs in operation from the bypass valve shown in my former Patent No. 1,430,577 for a fluid compressor, granted October 3, 1922, inasmuch as the present bypass valves are operated as a separate step of unloading while in said former patent, by-pass valves were operated as the fifth step of unloading in conjunction with the last two clearance chamber valves. In referring to the number of steps of unloading as five step or six step as the case may be, it is to be understood that full load constitutes the first positionof the valves and maybe considered the starting point of unloading and it the remaining steps comprise three-quarter load, one-half load, one-quarter load and no load, the regulation is regarded as five step control. In accordance with the present invention six step control is etiectedcont prising full load, tln'eecnarter load, onehalf load, o-nequarter load, no load, with all the clearance valves open but the bypass valves closed and the last or sixth step of complete unloading effected by opening all the by-pass valves and connecting pairs of clearance chambers between the ends of the cylinders. This last step is specially advantageous because it may be availed of in connection with the regulation and may be manually controlled as a start and stop unloader.

In accordance with the present invention, an adjunct or auxiliary automatic device Z is provided incon-junction with the main regulator and unloader X and cooperating therewith, but manually controlled at a distance as by means of the switch 32 from the main switch board 0 for the purpose of actuating the lever c of the regulator and partially or completely unloading the compressor at any desired time, regardless of the automatic control of the regulator.

The auxiliary device Z is preferably elecr -r p nsively n r lle by m ans of the solenoid 9 indicated diagrammatically in the drawings and connected by the leads 1' to the switch 29 on the switch board. The auxiliary device Z may be constructed in any suitable manner for the purposes indicated, but in this instance comprises the pressure cylinder 8 having the piston 6 provided with the stem u extending through the stuffing box 0 and having the adjustable tip in bearing under the outer end of the lever e. The supply and release of receiver pressure fluid for the cylinder 8, supplied by the pipe :1 and released through the atmospheric port 3 is controlled by the solenoid g, and operative connections between the armature z of the solenoid and the inlet and release valves 6 and 7 are indicated below the lower head 8 of the cylinder 8. When the piston or plunger t of the auxiliary device Z is moved upwardly by pressure, the weighted lever e of the main regulator is raised either partially or fully depending upon the adjustment of the set screw or stop 9 to either partially or'ifully unload the compressor while running or to completely unload the compressor when starting or stopping. As the pressure beneath the auxiliary plunger t is released, the weighted lever 6' falls and the. main regulator Z resumes automatic operation,

By manipulation of the auxiliary device Z from the switch board 0, excessive peak loads for the apparatus may be avoided, be cause if it is desired to start the hoist Q while the compressor is running under load, the solenoid switch 39 is first opened which deenergizes the solenoid supplies pressure fluid to the plunger t of the device Z and causes the stem 21 ot' the plunger to raise the weighted lever c which unloads the coinpressor. The hoist switch Von the switch board may then be closed. to start the hoist motor S and the compressor may run unloaded or partially unloaded while the hoist 1s running. This operation avoids the greatest peal; loads usually due to the starting of the hoist motor-and also due to conjoint operation of both the compressor motor and the hoist motor fully loaded.

In order to indicate to the switch board tender that the auxiliary device Z has caused the unloading of the con'iprcssor, a signal light 10 on the switch board is connected by the connections 11 to a switch 12 mounted adjacent the-auxiliary device Z and having a finger 13 adapted to be actuated by a member 14 to close and open the switch 12 as the plunger t moves upwardly and downwardly. The member 1 1 is carried by the stem 15 guided in the frame of the do vice Z and normally held in retractedposition by the spring 16. The end 17 of the stem iorms-a stop and a set screw 18 forms another stop for actuating the tongue or finger 13 of the switch. The arm 19 has a rod 20 suitably secured thereto and extending through the guide sleeve 21 on the auxiliary cylinder 8, so that the rod 20 follows the movement of the plunger Z and raises and lowers the member 14 to close and open the switch 12 and thus indicate to the switch board tender by means of the signal light 10 whether or not the compressor is un loaded. 7

The valves 6 and 7 for the auxiliary do vice Z may be in the "form of needle valves as shown provided with the valve springs 22 and the stems 23 ot the valves are adapted to be alternately actuated by the stops 24 carried by the pivotedlever 25, one end 26 of said lever engaging the stirrup 27 connected to the solenoid core Vvhen the solenoid Q is energized, the lever will be rocked on its pivot 28 to the position shown in Figure'2 in which case the valve 6 will be closed and the release valve 7 will be open and the plunger t will be in its lowermost position. Upon deenergizing the solenoid g, the solenoid core 2 falls and the position of the valves 6 and 7 is reversed so that pressure fluid from the receiver actuates the plunger 25 upwardly as hereinbefore clescribed. The upper portion of the cylinder 8 is preferably vented to atmosphere through the atmospheric vent 29.

The construction and operation of the main regulator X with the exception of the additional main operating valve in the casing Y is fully described and shown in my aforesaid Patent No. 1,430,578 so that this regulator will be but briefly described, reference being had to said patent for further details, The auxiliary or pilot valve 30 ot the regulator X is connected at the point 3]. to the weighted lever cand is provided with the heads 32 and 33 operating in the valve chamber 34. The space betweenthe heads 32 and 33 constantly subjected to receiver pressure through the ports 35 com municating with the pipe 36, subject to re ceiver pressure. Main operating valves 37 of which there are tour, are provided with the heads 38 and 39, and control the pipes 1, 2, 3 and 4 leading to the clearance valve casings 7s. The fifth main operating valve 37 is contained in the valve casing Y and controls the pipes 5 leading to the bypass valve casings 0. The main regulator X is provided with the atmospheric vent pipe 40 and the auxiliary casing Y of the regulator is provided with the atmospheric vent pipe 41. The shoes 42 of the main operating valves 37 control the ports 43 and 44. The spaces 45 between the valve heads 38 and 39 are constantly open to receiver pressure through the passages 46, and ports 1, 2, 3", and 4 controlled by the head 32 of the auxiliary valve 30, alternately supply pressure to-and release pressure from the heads 39 of the main valves 37, while ports 1 2 3 and 4 function in the same manner for the heads 38 of the valves 37. The passage 47 is open to atmosphere and communicates through appropriate ports and passages with the end faces of the valve heads 38. Obviously, as the shoes 42 ot the valves 37 move up and down, pressure is successively supplied from the valve spaces 45 to the pipes 1, 2, 3 and 4 leading to pairs of clearance alve casings Z: for holding the clearance valves closed and for successively 'releasing the pressure in said pipes through the ports 43 and 44 and the atmospheric vent 47. The valve 37 in the auxiliary valve casingY which controls the by-pass valves of the compressor operates in the same manner and is provided with auxiliary passages 48 and 49 leading to the ports 50 and 51 respectively which are also controlled by the valve heads 32 and 33 of the auxiliary valve 30. The valve 37 in the casing Y alternately supplies and releases pressure in the pipes 5 for the sixth step of unloading and loading.

I claim: A

1. In an inter-control system, the combination of two power driven devices and pneumatic means for decreasing the power consumption of one of said devices in anticipation of and only during the acceleration period of the other said device.

2. In a compressor, the combination of a cylinder and piston, an automatic pressure responsive regulator for unloading and loading the cylinder in successive steps, meanstor causing the regulator to unload the cylinder through a predetermined number of steps in one operation, a by-pass con-- nection between the ends of the cylinder, the last step of unloading comprising the opening of said by-pass connection, and an aux iliary electro-responsive device manually controlled from a distance cooperating with said regulator for actuating the regulator to complete unloading position at any desired time, whether the compressor is running full speed or starting or stopping.

3. In a compressor, the combination of a cylinder and piston, unloading devices for said cylinder including a by-pass connection between the ends ofthe cylinder and a bypass valve, an automatic pressure responsive regulator controlling said unloading devices and the bypass valve successively, the opening of the by-pass valve constituting the last step of unloading, means for causing the regulator to unload the cylinder through a predetermined number of steps in one operation, and an auxiliary electro-rsponsive device manually controlled from a distance for actuating the regulator to completely unload the compressor through all the steps at any desired time.

l. In a compressor, the combination of a cylinder and piston, an automatic pressure responsive regulator for unloading and loading the compressor in successive steps, an auxiliary cylinder and pressure actuated piston for causing the regulator to unload the cylinder through a predetermined number of steps in one operation, and electro-responsive means for controlling said auxiliary cylinder and piston, in turn manually controlled from a distance, whereby the comprcssor may be unloaded desired.

5. In a compressor, the combination of a cylinder and piston, an automatic pressure responsive regulator for unloading and loading the cylinder in successive steps, an auxiliary cylinder and pressure actuated piston for causing the regulator to unload the cylinder through a predetermined number of steps in one operation, and electro-responsive means r'or controlling said auxiliary cylinder and piston, in turn manually controlled from a distance, whereby the compressor may be unloaded and loaded at any desired intervals, regardless of the automatic action of the regulator.

6. In an apparatus of the class described, the combination of an electrically driven compressor and a second electrically driven power unit adapted to be operated intermittently, a main switch board and switches for the motors of the compressor and second unit, a pressure responsive regulator for unloading the compressor, an auxiliary electroresponsive device for causing the regulator to unload the compressor at will, and a controlling switch on the switch board for said auxiliary device, whereby the compressor may be unloaded while running to permit the second power unit to be started and thus avoid excessive peak loads. i In testimony whereof I have signed this specification.

CHESTER W. METZGAR. 

